PROFASI
Version 1.5

new_obs Rg rg2 of_chain 1 ; his_range 4 20 fixed ; his_bins 100
This sets up a new measurement of the radius of gyration, for the second chain in the population, with a histogram in the range 4, 20 with 100 bins. The histogram will maintain this range and number of bins throughout the run, without trying to adjust it. Out of range points will be lost.
new_obs Rg rg0 of chain 0; his_range 4 20 ; his_bins 100
This sets up a radius of gyration calculation for the first chain with a histogram that begins collecting data in the range 4 to 20 with 100 bins. But if the actual data is outside the range, the histogram range and number of bins are adjusted to cover the data, when that makes sense.
new_obs Rg rg make_histgram
This sets up a radius of gyration of all the atoms present in the population, and makes a histogram of the data.
new_obs Rg rg his_range 4.3 20 ; his_bin_size 0.25
This makes sure that histograms of the observable named rg are made with a bin size of 0.25. If necessary, the given range is symmetrically extended so as to contain an integral number of bins. In this example, the effective range would be 4.275 to 20.025.